Hydrion Spectral pH Strips (pH 0.0 to 14.0), Pack 100

Works well and fast. We use them for soap making and testing foods.

It appears the ph level is not 100 percent accurate. Ph level of 3 and 4 appears to be the same. I would be cautious of using it as a serious experiment.

I use these when making cold pressed soap. They work, but are sometimes hard to read.

I have no expertise in the field of chemistry; I just bought these strips for fun. And they are fun, and they have a full spectrum of clear colors that covers the whole pH range from 0 to 14 (a lot of pH strips and papers only cover part of the spectrum). But are they accurate? So far I have tested these items: red wine vinegar, baking soda mixed with water, tap water, sparkling water (Pellegrino), decaf Earl Grey tea, nonfat milk, and decaf Earl Grey tea with milk!The vinegar, the baking soda, and the milk came up with reasonable (according to internet research) pH numbers of 3.0, 9.0, and 6.5 (approximately, since the colors represent whole numbers). But the tap water, which should have a pH of 7, came up as about 4, or more like 4.25, and the Pellegrino as 5. Actually, the strips start at an orange color that corresponds to 4, and the tap water just didn't seem to change it. Anyway, if those numbers are accurate, that would make our tap water and the Pellegrino water somewhat acidic, but according to my internet searches and common sense, pure water should have a pH of 7. It's hard for me to believe that the tap water is so tilted to the acidic side, so I am a little skeptical about the accuracy of the strips, but I just got them and am going to continue experimenting. At least I'm having a good time.